The block, Masela PSC, is located about 800 km east of the Indonesian city of Kupang, and 400 km north of Darwin.
INPEX's two appraisal wells, Abadi-2 and Abadi-3, tested a total 32.4 million cubic feet a day of natural gas or 5,600 barrels a day of crude oil equivalent.
The major Japanese oil and gas producer acquired 100% of the development rights on the Masela block in 1998 from Indonesia's state-owned Pertamina under a production sharing contract.
INPEX's Indonesian unit, INPEX Masela, is the operator of the block.
